Topband: YCCC 9 circle preamp failure test

[VE6WZ_Steve]

Yesterday I decided to measure the actual voltage at base of my short HI-Z verticals while I transmitted on the TX array.

Since I first posted about the coupling capacitor failures in these units, I have received private emails form 4 others with the same problem.

My question is what has caused these failures? Is it a lightning event,  is it high-potential wind static on the vertical elements or is it from TX RF overload.

TX overload seemed possible at my location because my array is less that 100’ from the TX antenna.  I built a diode detector probe and in the field measured the actual voltage when TX.  The results indicate at most I see 50 v at the pre-amp.  The coupling caps are 63v rated units.  This would indicate that RF overload is not the cause, but I would really like thoughts and opinions from others.
I have redesigned the amps to include a relay to short out the antenna when not powered up, so I feel I am protected from any cause.

Here is a link to a YouTube video that shows the test set-up and the actual measurements I made in the field.  I also talk about using gas discharge tubes as a remedy.

https://youtu.be/TmM_YnLob68 <https://youtu.be/TmM_YnLob68>

73, de steve ve6wz